1. Field of the Invention
The present invention relates to the field of multiple load cell vehicle scales. More particularly, the invention is concerned with using statistical analysis to derive load position correction factors for a scale having a plurality of load cells.
2. Description of the Prior Art
A typical platform scale includes a platform supported by a plurality of load cells that are coupled with a signal processor. The load cells produce load signals representative of the weight experienced by each load cell. The signal processor processes the load cell signals to produce weight signals representative of the total weight of a load on the platform. The weight signals are derived from a combination of the load signals from the load cells.
However, the weight signals are subject to error due to the position of the load on the platform. That is, the same load at different positions on the platform may produce different weight indications. This is known as load position error. Load position correction factors must be derived for use with each of the load signals in order to compensate for this error.
One prior art technique for load position compensation is to place a given load in turn over each load cell on the platform. At each position, load cell readings are taken. These readings are used in a set of simultaneous equations, one equation for each load cell and one unknown (the correction factor) for each load cell. Algebraic techniques are used to solve these equations for the correction factors. However, these techniques use only one set of readings for each load position over a given load cell and thereby, cannot compensate for cyclic or random errors.